Systems and methods for removing organic compounds from steam

ABSTRACT

A system for producing steam includes a steam generator with steam output; a membrane filtration system in fluid communication with the steam output and including a membrane filter with a permeate side and an opposing retentate side. The membrane filter includes a separation membrane constructed to reject organic molecules. The system may be used for removing organic compounds, such as anti-corrosion agents or contaminants, from steam.

FIELD

The present disclosure relates to systems and methods for removingcompounds from steam. In particular, the present disclosure relates tosystems and methods for removing organic compounds, such as compoundsused as anti-corrosion agents, from steam.

BACKGROUND

Steam is used in many industries for various purposes, includingtransferring heat or thermal energy from a source to a point of use.Steam may be produced in various ways, including using a boiler, wherewater is heated to its boiling point. The water can be heated directlyor indirectly using a heat source, such as a burner, a heat exchanger,or an electric heater. Using direct heat boilers is most common, as thesystems are simpler, more efficient, and more cost-effective than, forexample, heat exchangers.

Due to the potentially corrosive nature of dissolved acids, such ascarbonic acid, in steam, it may be necessary to add anti-corrosionagents to the steam to protect the boiler and other parts of the system(e.g., metal piping). However, for some end uses of steam it would bedesirable to provide steam that does not contain anti-corrosion agentsor other compounds that are incompatible with the particular end use.

SUMMARY

The present disclosure relates to a system for producing steam, thesystem including a boiler with a steam output and a membrane filtrationsystem in fluid communication with the steam output. The membranefiltration system includes a first membrane filter with a permeate sideand an opposing retentate side. The membrane filter includes aseparation membrane adjacent the permeate side, the separation membranebeing constructed to reject organic molecules; and one or more supportlayers adjacent the retentate side.

The separation membrane may include a fluorinated (e.g., perfluorinated)polymer membrane (e.g., separation layer) and one or more support layerscomprising polyamide, polyimide, polysulfone, polyphenylene sulfide,PVDF, PTFE, or a combination thereof. The membrane filter may include aplurality of layers of separation membranes separated by spacers, wherethe spacers are constructed from polyamide, polyimide, polypropylene,polyethylene, PTFE, PVDF, or a combination thereof.

The system may include one or more additional filters upstream of themembrane filter or downstream of the membrane filter permeate side. Theone or more additional filters may include a second membrane filter, anadsorbent filter, a particle filter, or a combination thereof.

The system may be used to provide steam to a sterilizer, a humidifier,or a culinary steam outlet.

The present disclosure further relates to a method for removing anorganic compound from steam, the method including directing a cross-flowof pressurized steam having a first concentration of the organiccompound across a membrane filter. The membrane filter includes aseparation membrane constructed to reject the organic compound; and oneor more support layers adjacent the retentate side. The method furtherincludes collecting a steam permeate having a second concentration ofthe organic compound lower than the first concentration.

The organic compound may be an anti-corrosion agent, such as an amine.The first concentration may be greater than 20 ppm and the secondconcentration may be lower than 10 ppm.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a flow diagram of a steam supply system according to anembodiment.

FIG. 2 is a flow diagram of the steam supply system of FIG. 1 accordingto an embodiment.

FIG. 3 is a flow diagram of the steam supply system of FIG. 1 accordingto an embodiment.

FIG. 4A is a schematic perspective view of the membrane filter used inthe steam supply system of FIG. 1 according to an embodiment, where themembrane filter is shown partially unwound.

FIG. 4B is a schematic cross-sectional view of the separation membranein the membrane filter of FIG. 4A.

DETAILED DESCRIPTION

The present disclosure relates to systems and methods that are suitablefor removing compounds, such as organic molecules, from steam. Inparticular, the present disclosure relates to systems and methods thatare suitable for removing organic compounds, such as organiccontaminants or compounds used as anti-corrosion agents, from steam. Thesystems and methods of the present disclosure may be useful forpreparing clean steam for various end uses.

The term “alkylated” is used in this disclosure to describe compoundsthat are reacted to replace a hydrogen atom or a negative charge of thecompound with an alkyl group, such that the alkyl group is covalentlybonded to the compound.

The term “alkyl” is used in this disclosure to describe a monovalentgroup that is a radical of an alkane and includes straight-chain,branched, cyclic, and bicyclic alkyl groups, and combinations thereof,including both unsubstituted and substituted alkyl groups. Unlessotherwise indicated, the alkyl groups typically contain from 1 to 30carbon atoms. In some embodiments, the alkyl groups contain 1 to 20carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, 1 to 4 carbonatoms, or 1 to 3 carbon atoms. Examples of alkyl groups include, but arenot limited to, methyl, ethyl, n-propyl, n-butyl, n-pentyl, isobutyl,t-butyl, isopropyl, n-octyl, n-heptyl, ethylhexyl, cyclopentyl,cyclohexyl, cycloheptyl, etc.

The term “aryl” refers to a monovalent group that is aromatic and,optionally, carbocyclic. The aryl has at least one aromatic ring. Anyadditional rings can be unsaturated, partially saturated, saturated, oraromatic. Optionally, the aromatic ring can have one or more additionalcarbocyclic rings that are fused to the aromatic ring. Unless otherwiseindicated, the aryl groups typically contain from 6 to 30 carbon atoms.In some embodiments, the aryl groups contain 6 to 20, 6 to 18, 6 to 16,6 to 12, or 6 to 10 carbon atoms. Examples of an aryl group includephenyl, naphthyl, biphenyl, phenanthryl, and anthracyl.

The term “aromatic ring” is used in this disclosure to refer to aconjugated planar ring system of an organic compound. Aromatic rings mayinclude carbon atoms only, or may include heteroatoms, such as oxygen,nitrogen, or sulfur.

The term “amine” is used here to refer to compounds that include a basicnitrogen atom with a lone electron pair. Amines can be either primary(including functional group —NR¹H₂), secondary (including functionalgroup —NR¹R²H), or tertiary (including functional group —NR¹R²R³) TheR-groups may be independently selected, and may include alkyl groups,aryl groups, or halides.

The term “volatile” is used here to refer to compounds that have aninitial boiling point less than or equal to 250° C. measured at astandard atmospheric pressure of 101.3 kPa.

The term “substantially” as used here has the same meaning as“significantly,” and can be understood to modify the term that followsby at least about 75%, at least about 90%, at least about 95%, or atleast about 98%. The term “not substantially” as used here has the samemeaning as “not significantly,” and can be understood to have theinverse meaning of “substantially,” i.e., modifying the term thatfollows by not more than 25%, not more than 10%, not more than 5%, ornot more than 2%.

Relative terms such as proximal, distal, left, right, forward, rearward,top, bottom, side, upper, lower, horizontal, vertical, and the like maybe used in this disclosure to simplify the description. However, suchrelative terms do not limit the scope of the invention in any way. Termssuch as left, right, forward, rearward, top, bottom, side, upper, lower,horizontal, vertical, and the like are from the perspective observed inthe particular figure.

The terms “upstream” and “downstream” are used there to refer to aposition along the flow of steam from the stream generator to the pointof use. The steam generator is considered to be at or near the upstreamend of the system, and the point of use is considered to be at or nearthe downstream end of the system.

The terms “proximal” and “distal” are used to represent directionsrelative to a user using or holding the article. That is, the term“distal” is used to refer to the direction away from the user and towardthe applicator-end of the dispenser; and the term “proximal” is used torefer to the direction toward the user and away from the applicator-end.

The term “about” is used here in conjunction with numeric values toinclude normal variations in measurements as expected by persons skilledin the art, and is understood have the same meaning as “approximately”and to cover a typical margin of error, such as ±5% of the stated value.

Terms such as “a,” “an,” and “the” are not intended to refer to only asingular entity, but include the general class of which a specificexample may be used for illustration.

The terms “a,” “an,” and “the” are used interchangeably with the term“at least one.” The phrases “at least one of” and “comprises at leastone of” followed by a list refers to any one of the items in the listand any combination of two or more items in the list.

As used here, the term “or” is generally employed in its usual senseincluding “and/or” unless the content clearly dictates otherwise. Theterm “and/or” means one or all of the listed elements or a combinationof any two or more of the listed elements.

The recitations of numerical ranges by endpoints include all numberssubsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3,3.80, 4, 5, etc. or 10 or less includes 10, 9.4, 7.6, 5, 4.3, 2.9, 1.62,0.3, etc.). Where a range of values is “up to” or “at least” aparticular value, that value is included within the range.

The words “preferred” and “preferably” refer to embodiments that mayafford certain benefits, under certain circumstances. However, otherembodiments may also be preferred, under the same or othercircumstances. Furthermore, the recitation of one or more preferredembodiments does not imply that other embodiments are not useful, and isnot intended to exclude other embodiments from the scope of thedisclosure, including the claims.

According to some embodiments, the systems and methods of the presentdisclosure are suitable for removing compounds, such as organicmolecules, from steam. For example, the systems and methods of thepresent disclosure are suitable for removing organic compounds, such asorganic contaminants or compounds used as anti-corrosion agents, fromsteam. The systems and methods of the present disclosure may beparticularly useful for providing clean steam to end uses that needsteam without additives, such as anti-corrosion agents. Examples of suchend uses include humidification, sterilization, and culinary uses.

Anti-corrosion agents may be added to steam either in a boiler orin-line to prevent corrosion of various components of the system, suchas the boiler, pipes and lines (e.g., steel pipes), tanks, and otherelements that may come in contact with the steam. Some anti-corrosionagents may be added in the boiler but due to their non-volatile nature,remain there as the steam is let out of the boiler. However, someanti-corrosion agents are volatile, and vaporize and travel with thesteam downstream of the boiler. Examples of such anti-corrosion agentsinclude volatile amines (sometimes called “boiler amines” or“neutralizing amines”). While these agents have beneficial effectswithin the boiler system, they may be undesirable at the point of use.It may therefore be desirable to reduce the amount of or remove (e.g.,substantially remove) the agents prior to use.

Prior attempts to remove amines from steam include the use of packed bedadsorbent filters, such as those described in U.S. Pat. Nos. 3,424,548and 4,342,730. For example, U.S. Pat. No. 3,424,548 describes a metallicpressure cartridge constructed of stainless steel and containing anadsorbent resin, connected to a steam supply, and arranged such thatsteam enters the top of the cylinder and flows down through theadsorbent resin. The resin may be a material capable of adsorbing thevolatile amines in the steam, such as an inorganic hydrous oxide withcationic properties, e.g., zirconium phosphate or zirconium tungstate.U.S. Pat. No. 4,342,730 describes a system and method for purifyingsteam by passing the steam through a particulate filter and then a bedof ion-exchange resin material. The resin material is a strong-acid typepolymeric resin, such as a styrene copolymer, in hydrogen form, thatcaptures amines in an acid-base reaction. The resin may be able toremove amines from the steam so that the recovered steam has less than 3ppm of volatile alkaline material left. However, while packed bedfilters may be effective for removing volatile organic compounds fromsteam, they are typically not very efficient, suffering from a limitedcapacity. Packed bed filters typically need frequent regeneration andhave a limited lifetime before breakthrough of the volatile compoundsoccurs.

The systems and methods of the present disclosure are suitable forremoving organic molecules from steam. However, the systems and methodsare not limited to anti-corrosion agents only, and may be used to removeany undesirable organic components as long as a suitable filter membranecan be provided.

Referring now to FIG. 1, according to some embodiments, the steam supplysystem 1 includes a steam generator 10 having an inlet line 30 and asteam output 40. For example, the system 1 may include a steam generator10 such as a boiler, a heat exchanger, or an electrically heated steamgenerator. In one embodiment, the steam generator 10 is a boiler. Waterand/or steam is heated in the steam generator 10 by a heater 12 (see,e.g., FIG. 3). The steam generator 10 and the steam output 40 may have asteam capacity of at least about 10 lbs/hour (about 5 kg/h), at leastabout 100 lbs/hour (about 50 kg/h), at least about 500 lbs/hour (about200 kg/h), and/or up to about 1,000 lbs/hour (about 500 kg/h), up toabout 5,000 lbs/hour (about 2,000 kg/h), or up to about 10,000 lbs/hour(about 5,000 kg/h).

The steam supply system 1 may be part of a larger system, where thesteam output 40 is connected to one or more points of use. The system 1may also include a mechanism for adding anti-corrosion agents or othercompounds to the steam. For example, the system may include one or morestorage tanks and injections lines 32 for additives (e.g.,anti-corrosion agents). The additives may be injected directly into theboiler or into some other part of the system, e.g., an input linetransporting water into the steam generator or an output linetransporting steam from the steam generator. For example, the system 1may include an injection line 32 in fluid communication with the steamgenerator 10 (e.g., boiler).

According to an embodiment, the organic molecules are removed from thesteam in a membrane filtration system 20. It should be understood thatcomplete (100%) removal may not always be practical, and the term“remove” is used here to include partial removal (e.g., removing 50 wt-%or more, 60 wt-% or more, 70 wt-% or more, 80 wt-% or more, 90 wt-% ormore, 95 wt-% or more, 98 wt-% or more, or 99 wt-% or more).

The steam output 40 of the steam generator 10 (e.g., boiler) may be influid communication with a membrane filtration system 20 that includesone or more membrane filters 21. The membrane filter 21 has a retentateside 210 (e.g., feed side) and an opposing permeate side 220. Themembrane filter 21 includes a selective separation membrane 23 thatallows water molecules in vapor phase (e.g., steam) to pass through,while rejecting (e.g., retaining, not allowing to pass through themembrane) the organic molecules desired to be removed. The permeate(e.g., filtered steam) of the membrane filter 21 can be used at a pointof use 70 that is in fluid communication with the membrane filtrationsystem 20. The point of use 70 may be, for example, a sterilizer, ahumidifier, or a culinary steam outlet.

As shown in FIGS. 2 and 3, the membrane filtration system 20 may includeadditional filters in addition to the one or more membrane filters. Forexample, the membrane filtration system may include various sizes ofparticle filters 241, 243, 245, an adsorbent filter 22, or a combinationthereof. Particle filters may be used to remove solid particles orliquid droplets. The additional filters may be independently selectedand placed either upstream or downstream of the membrane filter 21(e.g., downstream of the permeate side 220 of the membrane filter 21.)In the exemplary embodiment shown in FIG. 2, the system includes amembrane filter 21 and an adsorbent filter 22 downstream of the membranefilter 21. In the exemplary embodiment shown in FIG. 3, the systemincludes a membrane filter 21, an adsorbent filter 22 downstream of themembrane filter, and multiple particle filters 241, 243, 245. Theparticle filters 241, 243, 245 may be positioned upstream or downstreamof the membrane filter 21. For example, particle filters 241, 243, 245of decreasing size cut-offs may be arranged upstream of the membranefilter 21, as shown. A particle filter may also be positioned downstreamof the adsorbent filter 22 to remove any fibers shed by the adsorbentfilter 22.

In some embodiments, the membrane filtration system 20 includes one ormore particle filters 241, 243, 245. The particles filters 241, 243, 245may have a size cut-off of about 2 mm, 1 mm, 500 μm, 200 μm, 100 μm, 80μm, 50 μm, 40 μm, 30 μm, 25 μm, 20 μm, 15 μm, 10 μm, 8 μm, 5 μm, 4 μm, 3μm, 2 μm, or 1 μm. The membrane filtration system may include acombination of two or more particle filters with different sizecut-offs. In one exemplary embodiment, a first particle filter 241 has aparticle size cut-off of about 1 mm; a second particle size filter 243has a particle size cut-off of about 25 μm; and a third particle sizefilter 245 has a particle size cut-off of about 5 μm. Each of theparticle filters 241, 243, 245 may further be associated with acorresponding trap 242, 244, 246 or drain for removing separatedparticulate matter from the system.

In some embodiments, the membrane filtration system 20 includes one ormore adsorbent filters 22. For example, the membrane filtration system20 may include adsorbent filters 22 as a polishing step to removeremaining organic molecules that were not removed by the membrane filter21. The adsorbent filter 22 may be arranged as a packed bed filter thatcontains an adsorbent and/or absorbent material, such as activatedcharcoal, a molecular sieve, other suitable materials, or a combinationthereof. The number and size of adsorbent filters 22 in the membranefiltration system 20 may be selected to achieve a desired capacity ofremoval.

A flow of steam (e.g., cross-flow 101 shown in FIG. 4A) entering themembrane filter 21 may have a first concentration of the organiccompound. The permeate 120 exiting the permeate side 220 of the membranefilter 21 at a first treated steam outlet 221 may have a second(reduced) concentration of the organic compound. If an adsorbent filter22 is included, the permeate 120 is further treated in the adsorbentfilter 22 and exits the adsorbent filter 22 at a second treated steamoutlet 222, having a third (further reduced) concentration of theorganic compound.

In embodiments where the membrane filtration system is used for removinganti-corrosive agents (e.g., amines) from the steam, the steam becomescorrosive after the treatment (e.g., removal of anti-corrosive agents),and it may thus be desirable to limit the exposure time of thedownstream components to the treated steam by positioning the membranefiltration system in relatively close proximity to the point of use. Forexample, the treated steam may have a residence time of about 10 secondsor less, about 5 seconds or less, about 2 seconds or less, about 1seconds or less, about 0.5 seconds or less, or about 0.1 seconds or lessbetween the first treated steam outlet 221 and the point of use 70,and/or between the second treated steam outlet 222 and the point of use70. In some embodiments, the first treated steam outlet 221 and/or thesecond treated steam outlet 222 may be positioned within 30 feet (10meters), or within 10 feet (3 meters), or within 3 feet (1 meter) fromthe point of use 70. Put another way, it may be beneficial for the line50 connecting the first treated steam outlet 221 and/or the secondtreated steam outlet 22 to the point of use to be 30 feet (10 meters)long or shorter, 10 feet (3 meters) long or shorter, or 3 feet (1 meter)long or shorter. The distances are given here as the linear length ofthe line 50 connecting the first treated steam outlet 221 and/or thesecond treated steam outlet 22 to the point of use.

The membrane filtration system 20 may include one or more membranefilters 21 to achieve a desired capacity for the membrane filtrationsystem 20. In embodiments where the membrane filtration system 20includes a plurality of membrane filters 21, the membrane filters 21 maybe arranged in parallel, in series, or a combination thereof.

In some embodiments, the membrane filters 21 are arranged as cross-flowfilters. A schematic depiction of a membrane filter 21 that can be usedin the membrane filtration system 20 is shown in FIG. 4A. The membranefilter 21 includes a separation membrane 23 selected to remove (e.g.,retain) the organic compound(s) of interest. A schematic cross-sectionalview of the separation membrane 23 is shown in FIG. 4B. The separationmembrane 23 may include a separation layer 230 that is supported by oneor more support layers 231, 232. In the exemplary embodiment shown, theseparation layer 230 is supported by a first support layer 231 and asecond support layer 232. The layers of the separation membrane 23 arearranged such that the first support layer 231 is on the permeate side220 and the second support layer 232 is disposed between the firstsupport layer 231 and the separation layer 230. When the steam reachesthe separation layer 230, the membrane allows water vapor to passthrough (e.g., permeate 120) to the permeate side 220, while rejectingthe organic compound molecules and retaining them (e.g., retentate 110)on the retentate side 210 of the membrane filter 21.

The membrane filter 21 may include a plurality of layers of separationmembranes 23. For example, the membrane filter 21 may be constructed asa wound roll of separation membranes 23, resulting in a cylindricalfilter structure with input flow of steam 101 at one end and outputflows of retentate 110 and permeate 120 at the other end. An example ofa wound membrane filter 21 is shown as partially unwound in FIG. 4A. Thelayers of separation membranes 23 may be separated by spacers 234. Theseparation membrane 23 itself may also include a spacer layer 235 tofacilitate flow of permeate 120.

The membrane filter 21 and the membrane filter system 20 may be made upof various components, such as the separation membrane 23, separationlayer 230, the one or more support layers 231, 232, spacers, adhesives,seals, sealants, housing, lines, connectors, etc. The materials of thecomponents of the membrane filter 21 and the membrane filter system 20may be selected so that (1) the membrane filter system 20 effectivelyremoves the organic compounds of interest from the steam, and (2) thematerials can withstand the high temperature and pressure environment ofthe steam supply system 1. Steam supplied by the steam generator 10 istypically at a temperature of 100° C. or greater, e.g., about 95° C. orgreater, about 100° C. or greater, or about 105° C. or greater, and/orup to about 135° C., up to about 140° C., up to about 150° C., or up toabout 175° C. The system 1, including from the boiler to at least theretentate side 210 of the membrane filter 21, may be under pressure. Forexample, the system 1 may have an internal pressure of greater thanatmospheric pressure, or of about 15 psi or greater, about 20 psi orgreater, about 25 psi or greater, about 30 psi or greater, or about 35psi or greater, and/or up to about 150 psi, up to about 100 psi, up toabout 80 psi, up to about 50 psi, or up to about 35 psi.

According to an embodiment, the materials of the membrane filter 21 andthe membrane filter system 20 do not substantially degrade in thepresence of steam at a temperature of about 95° C. or greater, about100° C. or greater, or about 105° C. or greater, and/or up to about 135°C., up to about 140° C., up to about 150° C., or up to about 175° C.;and/or at a pressure greater than atmospheric pressure, or about 5 psior greater, about 10 psi or greater, about 15 psi or greater, about 20psi or greater, or about 30 psi or greater, and/or up to about 150 psi,up to about 100 psi, up to about 80 psi, up to about 50 psi, or up toabout 35 psi. The materials may include the separation layer 230 and anysupport layers 231, 232, spacers 234, 235, adhesives, seals, sealants,housing, lines, connectors, etc., used in the membrane filtration system20.

The term “degrade” is used here generally to mean a change in thechemical structure or physical integrity (e.g., an elastic or plasticdeformation) of the material. The materials may be chosen to exhibitless than a threshold change (e.g., reduction) in a rheologicalindicator of material integrity (e.g., “material suitability criteria”).For example, the rheological indicator may be selected as tensilemodulus, stress at 10% tensile strain, stress at tensile break, and/orelongation at tensile break. The threshold may be selected to be about3%, about 4%, about 5%, about 6%, about 8%, about 10%, about 12%, orabout 15%. If, for example, a 5% threshold is selected, the materialsuitability criteria may be: less than 5% decrease in tensile modulus,less than 5% decrease in stress at 10% tensile strain, less than 5%decrease in stress at tensile break, and/or less than 5% deviation inelongation at tensile break. Degradation of the materials may be testedby exposing the material (e.g., a component prepared from the material)to a steam environment that simulates the steam supply system 1 for aselected period of time and evaluating the material for changes inrheological properties.

Preferred materials used in the membrane filter system include materialsthat are non-hydrolyzable in the steam environment. In some embodiments,the materials may be substantially free or free of polyesters,polyamides, cellulose acetates, or combinations thereof.

Another consideration when selecting materials for the system 1 istemperature fluctuations and different expansion rates of differentmaterials during such temperature fluctuations. For example, thetemperature (and pressure) of the system may fluctuate during start-upand shut-down of the boiler between atmospheric conditions and the steamenvironment conditions discussed above. Different expansion rates ofmaterials could lead to failure of materials, connections, or adhesives,or delamination of membrane filter layers. According to someembodiments, the materials are selected so that they exhibit equal orsimilar expansion during temperature fluctuations.

According to some embodiments, the separation layer 230 includes afluorinated (e.g., perfluorinated) polymer membrane. Suitable polymersfor preparing the separation layer 230 are disclosed, for example, inU.S. Pat. No. 8,828,121 (He et al.), and include copolymers of one ormore perfluorodioxolane monomers. Other polymers that are selective foran organic molecule of interest may also be used.

Preferably, the separation layer 230 has a high selectivity for H₂/N₂.For example, the separation layer 230 has a H₂/N₂ selectivity of 5 orgreater, 6 or greater, 7 or greater, 8 or greater, 9 or greater, 10 orgreater, or 12 or greater. While there is no desired upper limit for theH₂/N₂ selectivity of the separation membrane, in reality selectivitiesmay range up to about 100. Certain monomeric components, such astetrafluoroethylene (TFE), may result in lower selectivity of thepolymeric film. In some embodiments, the separation membrane does notinclude tetrafluoroethylene (TFE) in the polymeric structure. However,TFE may be included in a support layer, spacer, or other layers that arenot part of the separation layer.

In some embodiments the separation layer 230 includes a non-ionicfluorinated (e.g., perfluorinated) polymer membrane. In some embodimentsthe separation layer 230 is not an ion exchange membrane. The term “ionexchange membrane” is used here to refer to a membrane that includeschemical groups capable of combining with ions or exchanging ionsbetween the membrane and an external substance. Such chemical groups mayinclude sulfonic acid, carboxylic acid, phosphoric acid, phosphoricacid, arsenic groups, selenic groups, phenols, and salts thereof. Ionexchange membranes may require pretreating the membrane prior to use andperiodically regenerating the membrane with an ionic fluid (e.g., andacid or base).

The separation layer 230 is supported by one or more support layers(e.g., a first and second support layer 231, 232). Support layermaterials typically used in the prior art include cellulosic materials,which may not be able to withstand the steam environment. According tosome embodiments, the one or more support layers include polysulfone,polyphenylene sulfide (PPS), polyvinylidenedifluoride (PVDF),polytetrafluoroethylene (PTFE), polyphenylsulfone (PPSU, available undertradename RADEL® R from Ensinger, Inc. in Washington, Pa.),polyetherimide (PEI, available under tradename ULTEM® from Sabic inRiyadh, Saudi Arabia), polyetheretherketone (PEEK), polyethersulfone(PES), poly ethylene chlorotrifluoroethylene (ECTFE, available undertradename HALAR® from Solvay USA Inc in Princeton, N.J.), poly ethylenetetrafluoroethylene (ETFE, available under tradename TEFZEL® from DuPontin Johnston, Iowa), polyfluorinated ethylene propylene (FEP),polychlorotrifluoroethylene (PCTFE, available under tradename NEOFLON™from Daikin Industries, Ltd. in Osaka, Japan), perfluoroalkoxy (PFA,available under tradename NEOFLON™ from Daikin Industries, Ltd.), or acombination thereof. In one exemplary embodiment, at least one supportlayer is made from expanded PTFE.

The membrane filter 20 may include a plurality of layers of separationmembranes 230 separated by spacers 234, and wherein the spacers 234 areconstructed from polyamide, polyimide, polypropylene, polyethylene,PTFE, PVDF, polyester, or a combination thereof.

The membrane filter 20 may also include various adhesives. Preferably,the adhesives are selected to withstand the steam environment. Examplesof suitable adhesives include thermoset adhesives (e.g., epoxides,aldehyde-containing resins, and urethane-based adhesives), thermoplasticadhesives (e.g., acrylates).

Over time, the membrane filter system 20 may experience fouling that cancause blockage of filters, membranes, and other filter parts and/orreduce filter efficiency. Examples of possible foulants includeaccumulated particulate impurities and precipitated salts (e.g., saltsof amines and carbonic acid). To address fouling issues, the system mayinclude one or more mechanisms for removing accumulated materials. Forexample, the system may include parallel filters that can be used whilethe other filter(s) is being regenerated; a wash for washing a filter; abackwash or backflush for washing a filter by running reverse flowthrough the filter; a heater for heating a filter to remove accumulatedvolatile components; or a combination thereof.

The system may also include a temperature control unit for controllingthe temperature (e.g., maintaining a substantially constant temperature)downstream of the source of steam (e.g., boiler). The temperaturecontrol unit may include a temperature sensor (e.g., thermocouple), acontrol unit (e.g., microprocessor or any other suitable control unit),and a heating and/or cooling unit.

The membrane filter system 20 may include a mechanism for removingliquid water from the lines, and in particular from the line upstream ofand leading into the membrane filter. Steam reaching the membrane filter20 should be dry (i.e., not include liquid water) and substantially freeof particulates. Liquid water in a high pressure, high velocity steamsystem can cause damage to components, particularly membranes. In manyembodiments, a particle filter upstream of the membrane filter 20 mayserve as the mechanism for removing liquid water or water droplets.However, if the system does not include a particle filter upstream ofthe membrane filter, or if the upstream particle filter is not near themembrane filter, the system may include another mechanism, such asbaffles, a condensate trap, and/or a drain for removing liquid water.

In some cases, it may be desirable to reuse the organic componentremoved from the steam. For example, the organic component may be ananti-corrosion agent added to the steam in the boiler to preventcorrosion in the system. The anti-corrosion agent is removed before thesteam is used at the point of use. However, it may be desirable torecycle the anti-corrosion agent back to the boiler for reuse. Thus, insome embodiments the system 1 includes a return line 60 from theretentate side 210 of the membrane filter 21 to the boiler 10 or to aboiler feed line (e.g., inlet line 30 or injection line 32). The systemmay include a return line 60 from the retentate side 210 to both theboiler 10 and to a boiler feed line (e.g., inlet line 30 or injectionline 32).

The system 1 may also include additional components that are commonlyused in steam supply systems, such as a steam header, valves, condensatetraps, gauges, meters, various connecting lines, and the like.

Method

The treated (e.g., filtered) steam from the steam supply system 1 may beused at any point of use. However, points of use that mandate certainmaximum levels of organic molecules or organic contaminants mayparticularly benefit from the steam supply system 1 of the presentdisclosure. For example, the steam supply system 1 may be used toprovide clean steam to points of use such as humidification,sterilization, or culinary uses.

According to an embodiment, steam may be generated in the steam supplysystem 1 by heating water in a steam generator 10 (e.g., a boiler).Additives, such as anti-corrosive agents, may be added to the steamthrough an injection line 32, either directly into the steam generator10, or into an input or output line. In one embodiment, anti-corrosionagent (e.g., amine) is dispensed to the boiler at a concentration of 5ppm to 100 ppm. The anticorrosion agent may include one or more amines.In addition or alternatively, the steam may include other organiccompounds that may be undesired at the point of use.

Anti-corrosive agents are commonly added to steam to protect the boilerand other connected components from the corrosive effects of steam. Assteam is used and then condensed, carbon dioxide dissolves in the water,resulting in the formation of carbonic acid (H₂CO₃) and the lowering ofthe pH. The acidic water may then cause corrosion of piping andequipment. Anti-corrosion agents, such as neutralizing amines, may beused to alleviate the effects of low pH. Neutralizing amines hydrolyzein water, generating hydroxide ions that neutralize the acid.

Examples of amines that may be used as anti-corrosion agents includecyclohexylamine, morpholine, diethylaminoethanol (DEAE), anddiethylhydroxylamine (DEHA), methoxypropylamine, ammonia,2-amino-2-methyl-1-propanol (available from Angus chemical company asAMP-95), and 5,5-dimethyl-1-pyrroline-n-oxide (DMPO). Other suitableamines may also be used.

However, while amines or other anti-corrosive agents may be helpful inthe steam supply system, some end uses call for steam that issubstantially free or free of such components. For example, culinarysteam may be used in food production, where the steam may come intocontact with food ingredients or with surfaces used in the preparationof food. Additives permitted in culinary steam may be regulated by law,such as by C.F.R. Title 21, § 173.310 in the United States. Other useswhere additives may not be desired include the use of steam inhumidification and sterilization.

Steam may also include other organic compounds or organic contaminantsthat may be additives (i.e., intentionally added to the steam) or thatare present in the feed water into the steam supply system 1. The steamsupply system 1 may also be used to remove such other organic compoundsand organic contaminants. In particular, the steam supply system 1 maybe used to remove volatile organic compounds and contaminants.

According to an embodiment, steam from the steam generator 10 is lead tothe membrane filter system 20 through a steam output line 40. The steamleaving the steam generator 10 is typically under high pressure and/ortemperature, and may have a high flow rate. For example, the steam mayhave a temperature of about 95° C. or greater, about 100° C. or greater,or about 105° C. or greater, and/or up to about 135° C., up to about140° C., up to about 150° C., or up to about 180° C. The steam may be ata pressure of greater than atmospheric pressure, or of about 15 psi orgreater, about 20 psi or greater, about 25 psi or greater, about 30 psior greater, or about 35 psi or greater, and/or up to about 150 psi, 100psi, up to about 80 psi, up to about 50 psi, or up to about 35 psi.

The steam may first be lead through one or more particle filters, suchas the particle filters 241, 243, and 245 shown in FIG. 3. If aplurality of particle filters is used, the filters may be arranged fromcoarse to fine. Particles and condensate captured by the particlefilters may be trapped in corresponding traps 242, 244, 246. Afterremoving particulate matter from the steam, the steam is led into themembrane filter 21. According to an embodiment, the membrane filter 21is arranged as a cross-flow filter, and a cross-flow of steam 101 entersthe membrane filter 21 on the retentate side 210, where the targetorganic compounds (e.g., anti-corrosion agents, such as amines, ororganic contaminants) are retained and removed as retentate 110. Watervapor permeates the separation membrane 23 and enters the permeate side220 as permeate 120. The permeate 120 is substantially clean and drysteam that may be removed from the system and delivered to the point ofuse via output line 50. Optionally, the steam may be directed through anadditional filter 22, such as an adsorbent filter and/or an additionalparticulate filter. An adsorbent filter may be used as a polishing stepto remove trace amounts of organic compounds (e.g., anti-corrosionagents, such as amines, or organic contaminants) from the permeate.

The membrane filter 21, which may include multiple membrane filter unitseach housing a separation membrane 23 as described above, may beconstructed to reject (e.g., retain) at least 50 wt-%, at least 75 wt-%,at least 80 wt-%, at least 85 wt-%, at least 90 wt-%, at least 95 wt-%,at least 98 wt-%, at least 99 wt-%, or 100 wt-% of the organic compoundsof interest. The membrane filter 21 may be constructed to reject (e.g.,retain) at least 50 wt-%, at least 75 wt-%, at least 80 wt-%, at least85 wt-%, at least 90 wt-%, at least 95 wt-%, at least 98 wt-%, at least99 wt-%, or 100 wt-% of the organic compounds introduced to the membranefilter at a concentration of 1,000 ppm or less, 900 ppm or less, 800 ppmor less, 700 ppm or less, 600 ppm or less, 500 ppm or less, 400 ppm orless, 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less,40 ppm or less, 30 ppm or less, 20 ppm or less, or 10 ppm or less.

The cross-flow of steam 101 may have a first concentration of theorganic compound, and the permeate 120 may have a second concentrationof the organic compound. The first concentration of organic compound maybe 1,000 ppm or less, 900 ppm or less, 800 ppm or less, 700 ppm or less,600 ppm or less, 500 ppm or less, 400 ppm or less, 300 ppm or less, 200ppm or less, 100 ppm or less, 50 ppm or less, 40 ppm or less, 30 ppm orless, 20 ppm or less, or 10 ppm or less. The second concentration may beabout 1% or less, about 2% or less, about 5% or less, about 10% or less,about 15% or less, or about 20% or less of the first concentration. Theadsorbent filter may be constructed to remove at least 50 wt-%, at least75 wt-%, at least 80 wt-%, at least 85 wt-%, at least 90 wt-%, at least95 wt-%, at least 98 wt-%, at least 99 wt-%, or 100 wt-% of the organiccompounds of interest remaining in the steam permeate after the membranefilter 21. The filtered steam leaving the adsorbent filter may have athird concentration of organic compound, which may be about 1% or less,about 2% or less, about 5% or less, about 10% or less, about 15% orless, or about 20% or less of the second concentration (permeate 120).

For example, it may be desirable that the steam, while in the boiler 10and the lines leading up to the membrane filter 21, includes aconcentration (e.g., a first concentration) of about 20 ppm to about 200ppm of anti-corrosion agent (e.g., amine). It may further be desirablethat the treated steam leaving the membrane filtration system 20 (vialine 50) has a concentration (e.g., a second concentration) of less thanabout 10 ppm of anti-corrosion agent (e.g., amine). If the membranefiltration system 20 includes an adsorbent filter, the treated steamleaving the membrane filtration system 20 may have a concentration(e.g., a third concentration) of about 5 ppm or less of anti-corrosionagent (e.g., amine). In some preferred embodiments, the level of theanti-corrosion agent (e.g., amine) in the treated steam is at anon-detectable level (e.g., less than 1 ppm), or the treated steam issubstantially free of the anti-corrosion agent (e.g., amine).

The rejected (e.g., retained) organic compound may be re-used in thesystem. For example, retentate 110, which may include recoveredanti-corrosion agent (e.g., an amine), may be returned to the steamgenerator 10 (e.g., boiler) via a return line 60. The organic compound(e.g., anti-corrosion agent) is concentrated in the retentate 110, whichmay have a fourth concentration of the organic compound. The fourthconcentration may be about 10 wt-% or greater, about 20 wt-% or greater,about 50 wt-% or greater, about 80 wt-% or greater, or about 90 wt-% orgreater.

In one exemplary embodiment, anti-corrosion agent (e.g., amine) is addedto a boiler used to produce steam. The anti-corrosion agent (e.g.,amine) may be added at a concentration of 200 ppm or less, 100 ppm orless, 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, or10 ppm or less. Typically, anti-corrosion agent (e.g., amine) may beadded at a concentration of about 10 ppm to about 50 ppm. The steam fromthe boiler is then lead to the membrane filter system through a steamoutput line to remove or substantially remove the anti-corrosion agent(e.g., amine). The treated steam preferably contains anti-corrosionagent (e.g., amine) at a concentration of 10 ppm or less, 5 ppm or less,4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, 0.5 ppm orless, 0.2 ppm or less, or 0.1 ppm or less. The anti-corrosion agent(e.g., amine) removed from the steam as retentate may be reused, forexample, returned to the boiler via a return line.

The method may further include washing, backflushing, and/or cleaningsteps to remove accumulated particulates, precipitates, scale, or otherforms of fouling from the system. Washing and backflushing steps mayinclude washing or flushing with water and optionally with high or lowpH cleaning agents. Cleaning steps may further include heating andrinsing cycles. In some embodiments, the system includes parallelfilters (e.g., parallel particle filters, parallel membrane filters,and/or parallel adsorbent filters), and during a cleaning cycle, one ofthe parallel filters is cleaned while the other remains active.

Examples

The ability of three different membranes (A, B, and C) with differentH₂/N₂ selectivities to separate amines from steam was tested.

The membranes were tested in a laboratory scale system with a steam feedvapor mixture at 100° C. and atmospheric pressure. Steam was obtained byboiling deionized water containing either cyclohexylamine, morpholine ordiethylaminoethanol at 100 or 1,000 ppmw (parts per million by weight).A vacuum of 4 to 10 torr was maintained on the permeate side. Thepermeate was collected in a liquid nitrogen trap and analyzed for aminecontent by titration with 0.001 N Hydrochloric Acid or 0.01 NHydrochloric Acid, using an Ag/AgCl electrode (Thermo Scientific) and aVWR Symphony SB70-P pH meter.

Morphine, cyclohexylamine, and diethylaminoethanol were obtained fromSigma-Aldrich. Aqueous solutions of the amines were prepared usingdeionized water.

The membranes were characterized by their nitrogen gas permeance as:

-   -   Membrane A: 185 gpu (gas permeation unit) nitrogen permeance,        H₂/N₂ selectivity=6.6    -   Membrane B: 130 gpu nitrogen permeance, H₂/N₂ selectivity=7.8    -   Membrane C: 50 gpu nitrogen permeance, H₂/N₂ selectivity=12

About 800 cc of amine solution was brought to boiling at atmosphericpressure in a vessel with a membrane sample holder at the top. Thetested membrane was in contact with the vapor phase produced by theboiling process and the vapor was continuously recirculated over themembrane surface using a condensation/reflux mechanism. Permeation ofwater and amines was achieved by maintaining a vacuum in the range of 4to 10 torr on the permeate side. The permeate was collected in a liquidnitrogen trap. The performance of each membrane was tested separatelywith the three different amines.

The starting and ending concentrations of the amines in the solution andthe amine concentration in the permeate at the end of the experimentwere recorded. The average amine concentration in the solution duringthe test was calculated. The results are shown in TABLE 1 below.

TABLE 1 Test results Concentration Solution Solution Solution RejectionPermeance Start End Average Permeate Ratio: Feed/ Water (ppm) (ppm)(ppm) (ppm) Permeate (GPU) Membrane A Cyclohexylamine 1010 227 620 1364.6 2800 Morpholine 1020 1110 1060 99 11 2610 Diethylethanolamine 1020874 948 236 4.0 2500 Membrane B Cyclohexylamine 1030 749 890 17 52 2030Morpholine 1020 1150 1080 22 49 2350 Diethylethanolamine 875 725 800 3027 2120 Membrane C Cyclohexylamine 1020 413 714 7 102 1150 Morpholine993 1030 1010 11 92 949 Diethylethanolamine 1050 445 747 14 53 1150

It was observed that the water vapor permeance was the highest formembrane A and the lowest for membrane C. It was further observed thatall three membranes rejected the tested amines, and the highestrejection ratio was obtained with membrane C, which had a H₂/N₂selectivity of 12, highest of the three tested membranes. For membraneC, the rejection ratios were 102 for cyclohexylamine, 92 for morpholine,and 53 for diethylethanolamine. It was also observed that all membraneshad the highest rejection ration for cyclohexylamine, and the lowest fordiethylethanolamine.

ASPECTS

The following is a list of exemplary aspects of the articles accordingto the present disclosure.

According to aspect 1, a system for producing steam comprises: a boilercomprising a steam output; a membrane filtration system in fluidcommunication with the steam output, the membrane filtration systemcomprising: a first membrane filter with a permeate side and an opposingretentate side, the membrane filter comprising: a separation membraneadjacent the permeate side, the separation membrane being constructed toreject organic molecules; and one or more support layers adjacent theretentate side.

Aspect 2 is the system of aspect 1 further comprising an organicmolecule injection line operatively connected to the boiler.

Aspect 3 is the system of aspect 1 or 2, wherein the separation membranecomprises a perfluorinated polymer membrane.

Aspect 4 is the system of any one of aspects 1-3, wherein the separationmembrane comprises a one or more support layers comprising polyamide,polyimide, polysulfone, polyphenylene sulfide, PVDF, PTFE, or acombination thereof.

Aspect 5 is the system of any one of aspects 1-4, wherein the membranefilter comprises adhesives that do not substantially degrade in thepresence of steam at a temperature of about 95° C. or greater, about100° C. or greater, or about 105° C. or greater, and/or up to about 135°C., up to about 140° C., up to about 150° C., or up to about 180° C.;and/or at a pressure greater than atmospheric pressure, or about 5 psior greater, about 10 psi or greater, about 15 psi or greater, about 20psi or greater, or about 30 psi or greater, and/or up to about 150 psi,up to about 100 psi, up to about 80 psi, up to about 50 psi, or up toabout 35 psi.

Aspect 6 is the system of any one of aspects 1-5, wherein the membranefilter comprises a plurality of layers of separation membranes separatedby spacers, and wherein the spacers are constructed from polyamide,polyimide, polypropylene, polyethylene, PTFE, PVDF, or a combinationthereof.

Aspect 7 is the system of any one of aspects 1-6, wherein the organicmolecules comprise volatile organic contaminants.

Aspect 8 is the system of any one of aspects 1-7, wherein the organicmolecules comprise an anti-corrosion agent.

Aspect 9 is the system of any one of aspects 1-8, wherein the organicmolecules comprise an amine, and wherein optionally the amine may beselected from cyclohexylamine, morpholine, diethylethanolamine,diethylaminoethanol (DEAE), and diethylhydroxylamine (DEHA).

Aspect 10 is the system of any one of aspects 1-9, wherein theseparation membrane is constructed to reject at least 90 wt-% of theorganic molecules.

Aspect 11 is the system of any one of aspects 1-10 further comprising areturn line from the retentate side to the boiler or boiler feed line.

Aspect 12 is the system of any one of aspects 1-11 further comprising areturn line from the retentate side to the boiler and to the boiler feedline.

Aspect 13 is the system of any one of aspects 1-12 further comprisingone or more additional filters upstream of the membrane filter ordownstream of the membrane filter permeate side.

Aspect 14 is the system of aspect 13, wherein the one or more additionalfilters comprise a second membrane filter, an adsorbent filter, aparticle filter, or a combination thereof.

Aspect 15 is the system of aspect 13 or 14, wherein the one or moreadditional filters comprise one or more particle filters upstream of thefirst membrane filter.

Aspect 16 is the system of any one of aspects 13-15, wherein the one ormore additional filters comprise one or more particle filters downstreamof the permeate side of the first membrane filter.

Aspect 17 is the system of any one of aspects 13-16, wherein the one ormore additional filters comprise a second membrane filter arranged inparallel with the first membrane filter.

Aspect 18 is the system of any one of aspects 13-17, wherein the one ormore additional filters comprise a second membrane filter arranged inseries with the first membrane filter.

Aspect 19 is the system of any one of aspects 13-18, wherein the one ormore additional filters comprise a first adsorbent filter and a secondadsorbent filter arranged in parallel with one another.

Aspect 20 is the system of any one of aspects 13-19, wherein the one ormore additional filters comprise a first adsorbent filter and a secondadsorbent filter arranged in series with one another.

Aspect 21 is the system of any one of aspects 1-20 further comprising asecond filtration system comprising a second membrane filter, anadsorbent filter, or both.

Aspect 22 is the system of any one of aspects 1-21, wherein theseparation membrane does not substantially degrade at a temperature ofabout 95° C. or greater, about 100° C. or greater, or about 105° C. orgreater, and/or up to about 135° C., up to about 140° C., up to about150° C., or up to about 180° C.

Aspect 23 is the system of any one of aspects 1-22, wherein theseparation membrane does not substantially degrade at a pressure greaterthan atmospheric pressure, or about 5 psi or greater, about 10 psi orgreater, about 15 psi or greater, about 20 psi or greater, or about 30psi or greater, and/or up to about 150 psi, up to about 100 psi, up toabout 80 psi, up to about 50 psi, or up to about 35 psi.

Aspect 24 is the system of any one of aspects 1-23, wherein the steamoutput has a capacity of at least about 10 lbs/hour (about 5 kg/h), atleast about 100 lbs/hour (about 50 kg/h), at least about 500 lbs/hour(about 200 kg/h), and/or up to about 1,000 lbs/hour (about 500 kg/h), upto about 5,000 lbs/hour (about 2,000 kg/h), or up to about 10,000lbs/hour (about 5,000 kg/h).

Aspect 25 is the system of any one of aspects 1-24, wherein the systemis in fluid communication with a point of use comprising a sterilizer, ahumidifier, or a culinary steam outlet.

Aspect 26 is the system of any one of aspects 1-25, wherein the systemand the point of use are separated by a distance no greater than 10meters, no greater than 3 meters, or no greater than 1 meter.

According to aspect 27, a method for removing an organic compound fromsteam comprises: directing a cross-flow of pressurized steam comprisinga first concentration of the organic compound across a membrane filter,the membrane filter comprising: a separation membrane constructed toreject the organic compound; and one or more support layers adjacent theseparation membrane; and collecting a steam permeate comprising a secondconcentration of the organic compound lower than the firstconcentration.

Aspect 28 is the method of aspect 27, wherein the pressurized steam hasa temperature of about 95° C. or greater, about 100° C. or greater, orabout 105° C. or greater, and/or up to about 135° C., up to about 140°C., up to about 150° C., or up to about 180° C.

Aspect 29 is the method of aspect 27 or 28, wherein the pressurizedsteam has a pressure greater than atmospheric pressure, or about 5 psior greater, about 10 psi or greater, about 15 psi or greater, about 20psi or greater, or about 30 psi or greater, and/or up to about 150 psi,up to about 100 psi, up to about 80 psi, up to about 50 psi, or up toabout 35 psi.

Aspect 30 is the method of any one of aspects 27-29, wherein the organiccompound comprises an anti-corrosion agent.

Aspect 31 is the method of any one of aspects 27-30, wherein the organiccompound comprises an amine.

Aspect 32 is the method of any one of aspects 27-31, wherein the firstconcentration is greater than 20 ppm and the second concentration islower than 10 ppm.

Aspect 33 is the method of any one of aspects 27-32, wherein the secondconcentration is 1% or less, about 2% or less, about 5% or less, about10% or less, about 15% or less, or about 20% or less of the firstconcentration.

Aspect 34 is the method of any one of aspects 27-33 further comprisingrecovering a retentate comprising the organic compound.

Aspect 35 is the method of any one of aspects 27-34 further comprisingreusing the organic compound.

Aspect 36 is the method of any one of aspects 27-35 further comprisinggenerating the steam in a steam boiler and returning the retentate tothe steam boiler or boiler feed line.

Aspect 37 is the method of any one of aspects 27-36 further comprisinggenerating the steam in a steam boiler and returning the retentate tothe steam boiler and boiler feed line.

Aspect 38 is the method of any one of aspects 36-37 further comprisingdispensing anti-corrosion agent to the boiler at a concentration of 5ppm to 100 ppm.

Aspect 39 is the method of aspect 38, wherein the anti-corrosion agentcomprises one or more amines.

Aspect 40 is the method of aspect 39, wherein the amines are selectedfrom cyclohexylamine, morpholine, diethylethanolamine,diethylaminoethanol (DEAE), and diethylhydroxylamine (DEHA).

Aspect 41 is the method of any one of aspects 27-40 further comprisingpassing the steam permeate through a second membrane filter or anadsorbent filter.

Aspect 42 is the method of aspect 41, wherein a treated steam outputafter the second membrane filter or the adsorbent filter has a thirdconcentration of the organic compound, and wherein the thirdconcentration is less than 5 ppm, or wherein the third concentration isabout 1% or less, about 2% or less, about 5% or less, about 10% or less,about 15% or less, or about 20% or less of the second concentration.

Aspect 43 is the method of any one of aspects 27-42, wherein theseparation membrane comprises a perfluorinated polymer membrane.

Aspect 44 is the method of any one of aspects 27-43, wherein theseparation membrane comprises a one or more support layers comprisingpolyamide, polyimide, polysulfone, polyphenylene sulfide, PVDF, PTFE, ora combination thereof.

Aspect 45 is the method of any one of aspects 27-44 further comprisingwashing, back flushing, or heating the membrane filter.

Aspect 46 is the method of any one of aspects 27-45 further comprisingwashing, back flushing, or heating the adsorbent filter.

Aspect 47 is the method of any one of aspects 27-46, wherein the steampermeate has a retention time of less than 10 seconds or less, about 5seconds or less, about 2 seconds or less, about 1 seconds or less, about0.5 seconds or less, or about 0.1 seconds or less between a treatedsteam outlet and a point of use.

Aspect 48 is the method of aspect 47, wherein the treated steam outletis an outlet of the membrane filter.

Aspect 49 is the method of any one of aspects 27-48, wherein thecross-flow of the pressurized steam has a flow rate of about 10 lbs/hour(about 5 kg/h) to about 10,000 lbs/hour (about 5,000 kg/h).

All references and publications cited herein are expressly incorporatedherein by reference in their entirety into this disclosure, except tothe extent they may directly contradict this disclosure. Althoughspecific embodiments have been illustrated and described herein, it willbe appreciated by those of ordinary skill in the art that a variety ofalternate and/or equivalent implementations can be substituted for thespecific embodiments shown and described without departing from thescope of the present disclosure. It should be understood that thisdisclosure is not intended to be unduly limited by the illustrativeembodiments and examples set forth herein and that such examples andembodiments are presented by way of example only with the scope of thedisclosure intended to be limited only by the claims set forth here.

1. A system for producing steam, the system comprising: a boilercomprising a steam output; a membrane filtration system in fluidcommunication with the steam output, the membrane filtration systemcomprising: a first membrane filter with a permeate side and an opposingretentate side, the membrane filter comprising: a separation membraneadjacent the permeate side, the separation membrane being constructed toreject organic molecules; and one or more support layers adjacent theretentate side.
 2. (canceled)
 3. The system of claim 1, wherein theseparation membrane comprises a perfluorinated polymer membrane.
 4. Thesystem of claim 1, wherein the separation membrane comprises a one ormore support layers comprising polyamide, polyimide, polysulfone,polyphenylene sulfide, PVDF, PTFE, or a combination thereof. 5.(canceled)
 6. The system of claim 1, wherein the membrane filtercomprises a plurality of layers of separation membranes separated byspacers, and wherein the spacers are constructed from polyamide,polyimide, polypropylene, polyethylene, PTFE, PVDF, or a combinationthereof.
 7. The system of claim 1, wherein the organic moleculescomprise volatile organic contaminants, optionally wherein the volatileorganic contaminants comprise an amine.
 8. (canceled)
 9. (canceled) 10.The system of claim 1, wherein the separation membrane is constructed toreject at least 90 wt-% of the organic molecules.
 11. The system ofclaim 1 further comprising a return line from the retentate side to theboiler or boiler feed line or both.
 12. (canceled)
 13. The system ofclaim 1 further comprising one or more additional filters upstream ofthe membrane filter or downstream of the membrane filter permeate side,the one or more additional filters comprising a second membrane filter,an adsorbent filter, a particle filter, or a combination thereof. 14.(canceled)
 15. (canceled)
 16. (canceled)
 17. The system of claim 13,wherein the one or more additional filters comprise a second membranefilter arranged in parallel or in series with the first membrane filter.18. (canceled)
 19. The system of claim 13, wherein the one or moreadditional filters comprise a first adsorbent filter and a secondadsorbent filter arranged in parallel or in series with one another. 20.(canceled)
 21. (canceled)
 22. The system of claim 1, wherein theseparation membrane does not substantially degrade at a temperature ofabout 100° C. to about 180° C. and/or at a pressure of above atmosphericpressure and up to about 100 psi.
 23. (canceled)
 24. (canceled)
 25. Thesystem of claim 1, wherein the system is in fluid communication with apoint of use comprising a sterilizer, a humidifier, or a culinary steamoutlet, and wherein the system and the point of use are separated by adistance no greater than 10 meters.
 26. (canceled)
 27. A method forremoving an organic compound from steam, the method comprising:directing a cross-flow of pressurized steam comprising a firstconcentration of the organic compound across a membrane filter, thepressurized steam having a temperature of about 100° C. to about 150° C.and a pressure of above atmospheric pressure and up to about 100 psi,the membrane filter comprising: a separation membrane constructed toreject the organic compound; and one or more support layers adjacent theseparation membrane; and collecting a steam permeate comprising a secondconcentration of the organic compound lower than the firstconcentration.
 28. (canceled)
 29. (canceled)
 30. (canceled)
 31. Themethod of claim 27, wherein the organic compound comprises an amine. 32.The method of claim 27, wherein the first concentration is greater than20 ppm and the second concentration is lower than 10 ppm.
 33. The methodof claim 27, wherein the second concentration is 10% or less of thefirst concentration.
 34. The method of claim 27 further comprisingrecovering a retentate comprising the organic compound and reusing theorganic compound.
 35. (canceled)
 36. The method of claim 27 furthercomprising generating the steam in a steam boiler and returning theretentate to the steam boiler or boiler feed line or both the steamboiler and the boiler feed line.
 37. (canceled)
 38. The method of claim36 further comprising dispensing anti-corrosion agent to the boiler at aconcentration of 5 ppm to 100 ppm.
 39. The method of claim 38, whereinthe anti-corrosion agent comprises one or more amines selected fromcyclohexylamine, morpholine, diethylethanolamine, diethylaminoethanol(DEAE), and diethylhydroxylamine (DEHA). 40.-49. (canceled)